As a side note, while reading these commands,

I think 'windmove-display-same-window', 
'windmove-display-new-frame',
'windmove-display-new-tab' are not really at they own place in 
windmove.

We have already "C-x 4 1" (same-window-prefix) and "C-x 5 5"
(other-frame-prefix) and (other-tab-prefix) --that is not bound to 
any
key on my system but would eventually have its place in the "C-x 
t" map.

Should we --for these windmove-commands :
 1. keep them as they are
 2. make aliases and clean-up 'windmove-display-in-direction'
 3. delete them and clean-up 'windmove-display-in-direction'
?

Since it becomes to get off the topic with the removal of the
:group tag, I can start another patch "clean-up" if requested.